Bent-tube evaporator



1927' R. c. JONES BENT TUBE EVAPORATQR Filed Sept. 16 1921 4 Sheets-Sheet 2 oooooooooooooooooooooo 00000 ooooooooooooooooooooooooooo I ooooo ooooooooooo oooooooo o,

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R. C. JONES BENT TUBE EVAPORATOR 4 Shegets-Shegt 4 Filed Sept 16. 1921 avwemtoz 131 abliomag; M Am d, f/zwzu, xW

Patented Feb. 8, 1927.

UNITED RUSSELL e. JONES, or BRONXVILLE, NEW YORK, ASSIGNOR TO THE earseom museum.

COMPANY, or nnwyonx, n.

a conrona'rron' or DELAWARE.

BENT TUBE EVAIPORA'JSOR! Application filed September 16, 1921. Serial No. 561,058,

. ing sea water or oth erimpure water to oh- I described 'in tain'pure water for boiler feed orother purposes.

One of the chief difficulties-with evapora-.

'tors of this class is due to the fact that sea water andwaters generally of such impurity that they must be'distilled' before use as boiler feed have marked scale-forming properties so that thesurface of the heating tubes in the evaporator rapidly loses its efficiency due to accumulated scale unless the evaporator. is shut down and the tubes cleaned at frequent intervals. i

The principal object of my present invention is to provide an evaporator in which the tubes are self-cleaning. or substantially so, whereby'the' evaporators may be kept in substantially 'constant'use with their heattransferringsurfaces at high efficiency.

A further object of the invention is to provide van evaporator of this class in which a large area of heating surface may be provided in an apparatus of moderate size, thereby increasing the vapor output in relation to the size and weight of the appara-' tus. This feature of the invention is of particular importance in. evaporators for use on shipboard where the conservation of space is a factor of greatest importance. A further object of the invention is to --'provide' an evaporator which is of simple design and low manufacturing cost and which may be readily taken down for the replacement of a idefective tube or other purpose.

With the above objects in View my invention consists ofthe construction shown and the accompanying drawings, 'wherein- Y 1 Fig. 1 is a vertical longitudinal section of an evaporator constructed according to my invention; I

Fig. 2 is a transverse section on line 2-2 Of Fig. 1;

Referring to the drawings, 1 indicates the evaporator shell, hereshown as of the horitilirough'the outlet port 4:. The front end 5 of the evaporator is detachably connected to the sh'ellby bolts in the flanges to. give access to the interior of the shell and permit the withdrawal of the'heating tubes, etc. The heating surfaceis provided in the form-of adarge number of slightly bowed horizontal tubes 7 the "tubes being preferably arranged in a bundle as indicated in Fig.

2. The' tubes are preferably arranged in horizontal and vertical rows and are supported at each end in tube sheets '8 and 9, respectively." The tube sheet 8 forms the rear wall of a manifold chamber 10 which receives the steam from the seam main 1]. pass ing, through the side wall of the shell, as shown in Fig. 2, and connected with an n per dome-like extension 12 of the manifo d chamber 10. The dome 12 connects with the steam main by a flanged couplin 13 arranged -to'have itsline "of separation in a vertical plane. Also,"the drain connection 14 for the tube bundle is attached to the drain line 15 of the shell by a similar flanged coupling 16, whereby when-it is desired to withdraw the tube bundle it is necessary merely to detach the two flanged couplings 13 and-lfiand withdraw the tube bundle through the open front end of the evaporator shell, the tube bundle being for this purpose preferably supported on inclined rails 18' attached to the bottom of the shell.

All of the tubes 7 are connected to the steam manifold 10 which is divided by a transverse partition 19 into an upper and a lower chamber, the lower chamber having an open connection withthe drain line 14 as shown in Fig. 1. Y

At the rear end of the tube bundle all of the tubes connect with a common chamber concave cover p1'ate'21, the arrangement being such that all the tubes except the two bottom rows serve as condensing surfaces for the live steam from the steam main 11', while the two'bottom rows serve principally as drain returns for the condensed steam which collects in the tubes of the upper division and isblown by the steam pressure into 20 formed between the tube sheet 9 and the the chamber 20 whence it drains through the bottom tubes into the lower chamber of the manifold and thence into the drain line.

The tubes"? are of small bore, which not only gives them a large surface in proportion to their cross sectional area, but keeps that surface active by reason of the fact that T steam pressure.

, bolts 23 of suficient strength to resist elongation under the pressure resulting from the expansion of all the tubes in the tube bundle.

My improved evaporator is sell-scaling, and this ll obtain by having the tubes slightly bowed in the manner shown; the bowingbeing somewhat exaggerated in order to be readily apparent.

In Fig. l l in vertical planes, the opposite ends of each tube being supported in the tube sheets 8 and 9 at substantially the same height, while the central portion of the tube is bowed upwardly so that liquid condensed along the length of the tube may find its way out at one end or the other under the influence of ravity alone. Thetubes should be bent to just a sutllcient extent to give a lateral directionto the middle of the tube when the tube is elongated through expansion, and the smaller the degree of bow within such limits as necessary to protect the tubes from rupture, the greater will be the surface distortion of the tubes for the same degree of elongation.

To increase the efiiciency of the evaporator 1 preferably cover the tube bundle'with an inverted U-shaped submerged bafil'e 24 gen erally similar to that employed in the multicoil evaporator shown anddescribed in my prior U. S. Patent No, 1,299,955, granted April 8, 1919. This bathe may conveniently be supported'on the tie-rods 23 by means of stirrups 25, as shown in Fig. 2. v

For facilitating the cleaning of the bores of the tubes, and for facilitating the removal of a detective tube the outer face of the manifold chamber 10 is provided with a cover plate 26 the removal of which, to-

gether with the removal of the cover plate 21, gives free access to both ends of the tubes.

Figs. 3 tov 5 illustratea modified form of apparatus embodying my invention. I have illustrated in these figures a type of evaphave shown the tubes bowed 'tion of the tie-rods,

orator in which the tube bundle-is built in I as an essentially integral part of the evaporator unit, in contrast to the removable tube bundle as illustrated in Figs. 1 and 2.

The tube sheets 8 and 9, into'which the ends of tubes 7 are secured, are extended so as to completely enclose the shell and thus constitute the end walls of the evaporator,

-a door 27 being-provided in one ot'the walls I The sheets head 26 having an inlet27 is secured to tube sheet 8 and is in direct communication with the inlet ends of tubes 7. Likewise, a cham ber 21 having an outlet 15 is secured to tube sheet 9 and is in direct communication with the discharge ends of tubes 7. Steam is admitted at the opening27' into chamber 26,

from whence it divides evenly among the severaltubes constitutingthe heating element of the evaporator and is condensed therein. The condensate and any vapor which may still remain uncondensed is discharged into chamber 21 and is removed by means of outlet 15.

The tube bundle 7 may be rectangular in shape as shown in Fig.2. or it may be approximately c rcular in shape, as. indicated in Fig. 4,.the tube ends being preferably spaced in the tube sheet at equal distances from each'other to form a series of horizontal and vertical rows. I have here shown the tubes slanted somewhat from a true horizontal direction to facilitate their proper drainage. As shown inFig. '5, the tubes of the bundle are bent in transverse planes rather than in vertical planes. All of the tubes may be bowed in the same direction, if desired, but I preferably bow alternate transverse rows in opposite directions as shown for the purpose of equalizing stresses which occur on the tube sheets 8 and El during expansion and contraction of the tubes and which would otherwise have to be taken up by the tie-bolts Q3.

i The tubes are scaled by causinga quick expansion or contraction .ot the tubes without a corresponding. expansion or contrac- This may be accomplished by filling the evaporator shell with cold water and admitting steam to'the tubes, or with the hot water still in the shell the tubes may be flushed-with cold water. The

elongation or shortening of the'tubcs will produce a distortion of the tube surface which will crack-and loosen the scale so that it will drop oil particularly when the heating surface becomes active. in the normal operation of the evaporator. The feed lines for the shell and tubes will be provided with 7 suitable cold water connections and valves so that the scaling may be ell'ccted without bundle is provided as a removable unit and.

taking the evaporator down and with only a brief interruption of the operation of the evaporator plant.

The arrangement of tubes in a horizontal bundle detachable as a unit in the manner shown in Figs. 1 and 2, is of particular advantage in cleaning the tube bores and replacing a defective tube. In fact, the tubes may be cleaned without removing the bundle fionrthe evaporator bytaking otfihe detachable side of the evaporator shell and the detachable head of the manifold at the end of the tube bundle. The tube" bundles may also be made interchangeable so that a readyset-up bundle may be quickly substituted for the bundle in use should more or less extensive repairs be required on the latter.

It is to be noted that I haveillust-rated a type of evaporator shell in which the tube also a type of evaporator in which the tubes are built in to the evaporator walls and must be removed individually. I have fur-- ther' illustrated the removable tube bundle as composed of a plurality of tubes bent ih vertical planes, but it is obvious that the tubes of this bundle may equally well be bent in horizontal planes. Likewise, alternate horizontal rows may be bent in alternate directions similar to the construction shown' in Fig. 5 or alternate vertical'rows of tubes may be bent oppositely, provided sufiicient slant be given thosetubes which are bowed downwardly so that water of condensation may drain freely from the tubes under the influence of gravity alone. Likewise, the type of evaporator employing a built in tube bundle is not confined to the tube construc-' tion shown. but may embody a tube bundle in which theftubes' are bowed in vertical planes, or in any other desired manner. That "is, my invention resides broadly'in an evaporator equipped with a tube bundle inwhich-the individual tubes are slightly bowed .outof a straight line connecting their ends, the exact manner and direction ofbowing as wellas the slant imparted to the tubes or the type of individual shell employed being dependent upon conditions affecting each particular installation.

In the accompanying drawings and foregoing description I have disclosed my imroved evaporator as of the horizontal type but it will, of course, be understood that the improvements may be applied to other types of evaporators and that the details of construction may be variously modified without departing from the spirit of the invention.

I claim: 3

1. In an evaporator, the combination of a shell for the liquid to be evaporated having a detachable portion at one end to giveaccess to its interior, a series of heating tubes therein arranged horizontally of the shell and positioned in substantial parallelism, tube sheets in which the opposite ends of. said tubes are supported, said tubes and tubeg sheets forming a unitary tube bundle, an inlet passage at one end of said tube bundle connecting with a large portionof said tubes, a chamber at the other end of said bundle "in communication with all of said .tubes, and a discharge passage adjacent said impurities comprising a shell for containing the liquid to be evaporated, a heatin element at least partly submerged in said iquid and comprising a seriesof tubes, tube sheets in which the ends of said tubes are supported, said tubes being slightly bowed, and tie bolts extending between said tube sheets .for maintaining said tube sheets against 'i'ree relative movement under the expansion and contraction of said tubes, whereby changes in temperature of the heating tubes will cause an appreciable bending or straightening of the tube to thereby exfoliate the scaly deposit of impurities accumulated on said tubes. 4

3. An evaporator for producing purified vapor from liquid containing scale forming impurities comprising a shell for containing the liquid, a heating element extending into said liquid and comprising a series of tubes of small bore grouped together in a tube bundle in substantial parallelism along their entire length, a portion of said tubes being slightly bowed in one direction away from a straight axial line, a second portion of said tubes being bowed in another direction away from parallelism with said line, and means independent of said shell for supporting the ends of said tubes and maintaining the ends,

of the tubes against free relative movement under the expansion and contraction of said tubes, whereby changes in temperature will produce an appreciable flexure along a sub- :tantial portion of the length of each tube and thereby exfoliate accumulatedscale.

ing water involvin the deposit of scaleforming substances mm the water, the combination" of a vessel, a heating element therein com rising a plurality of heat-transferring tu es arranged in substantial parallel- 4. In an apparatus-for heating: and treat ism, tube sheets supporting the endsof said tubes, means independent of said shell formaintaining said tube sheets against separaproduces a relativelylarge deformation of the metal of the tube and thereby exerts a.

loosening action on the deposited scale.

In an apparatus for heating and-treating liquids involving the deposit of scaleforming materials, the combination of .a vessel, :1 heatin ele'ment therein consisting of a plurality ol ranged in substantial parallelism, said tubes being slightly offset at their middle portions, the extent of such ofi'set being just sutfioient for elongation of the tube through heat expansion toproduce a further bowing of the tube instead of rupturing it, and means independent of said'vessel for holding said tube sheets against the thrust occasioned by the elongation otsaid tubes.

6. In an-evaporator, the combi ation of a shell for the liquid to be evaporated having a detachable portion at one end to give access to its interior, a removable heating element comprising a pair of tube sheets having a plurality of heating tubes extending therebetween, said tubes being arranged in substantial parallelism along their entire length, and means forming a part of said removable heating element for maintaining said tube sheets against free relative movement under the expansion and contraction of said tubes, said tubes being bowed away from a straight axial line sufficiently to prevent rupture but notsufliciently to prevent a substantial exfoliation of the scaly deposit of impurities accumulated on the tubes by bending or straightening of the tubes under change in temperature. a

v7. In an apparatus for heating and treating water involving the deposit of scaleforming substances from the Water, the combination of a vessel, a heating element therein com rising a plurality of heat transferringtu es arranged in substantial parallelism, tube sheets supporting the ends ofsaid tubes, said tubes and tube sheets being removable'as a unit from the vessel, and means fQrming'a'part of said removable-unit for maintaining said tube sheets against sepa ration through the expansion of said tubes,

'- said tubes being slight] "bowed out of a straight line whereby re ative'ly smallelonheat-transferring tubes a'I gationvof the tubes through heat expansion produces a relatively large deformation of the metal of the tube and thereby exerts a loosening action upon the deposited scale.

8. In an apparatus for heating and treating liquids involving the deposit of scaleforming materials, the combination of a vessel, a removable heating element therein consisting o f a plurality of heat transferring tubes arranged in substantial parallelism, said tubes being slightly oflset at their middle portions, the extent of such ofi'set being just sufiicient for elongation of the tubes through heat expansion to produce a further bowing of a tube instead of rupturing it, and means forming a part of said removable heating element for holding said tube sheets against the thrust occasioned by the elongation of said tubes. j

9. In an evaporator, the combination of a shell for the liquid to be evaporated having a detachable portion at one end to give access to its interior, a removable heating element comprising a plurality of heating tubes positioned in substantial parallelism, tube sheets in which the opposite ends of, the tubes are supported, a header associated with the front tube sheet having inlet and outlet joint surfaces at right angles tothe axis of the heating element, said inlet communicating with a large portion'of said tubes and said outlet communicating with those tubes not in communication-with said inlet, and a chamber at the other end of the removable heating unit in communication with all of said tubes, an intake passage provided on said shell for conveying heating fluid to the apparatus, a discharge passa e on the shell for receiving fluid discharge paratus, detachable connections betweenthe respective intake and discharge passages on the shell and the inlet and outlet- 'of the heating element header, a pair of rails within the shell upon which the heating element is slidabletoand from its operative'position, said detachable connections. having joint surfaces positioned in horizontal alignment with the joint surfaces on the heating element header Whenthe heating element is supported on said rails, and the planes of the joint surfaces of said detachable connections being disposed so as to contact 'with the joint surfaces of the header when the heating element. is slid into' its operative position within theshell. a

In testimony whereof- I affix my signature.

' RUSSELL C. JONES.

from the ap- 

